System for energizing space discharge devices



M y 935- B. F. MIESSNER 48 I I SYSTEM FOR ENERGIZING SIiACE DISCHARGE DEVICES Original Filed May 3, 1929 V UNITED S A Patented y-14, 1935 Benjamin F. Miessner.

Fort ENERGIZING sPAoE DIS- onAaoE DEVICES I Short Hills, N. L, assignor,

.by mesne assignments, to Radio Corporation of America," New York,

' Delaware N. Y.', a corporation, of

Application May 3,: 1929, Serial No. 360,045 I Renewed October 22, 1931 I 20 Claims. ((31.179-1'71) invention :relates to' energizing multiple electrode vacuumtubes and, like space discharge devices for operation from unsteady sourcesof current energyso as to limit, control or neutral:

t ize thewefiects of theunsteady current energizing,

1 and in particular to avoid hum production. in systems employing such tubes for amplifying sound reproducing currents; and electrical phonographic reproducers'in particular being contemplated. y My, present invention-has for a particular object hum eliminationor control with theaid of an additional electrode over theusualthree electrode vacuum tube construction, such as the four electrode r tube, commonly termed shielded grid type now promising to enter into more general use. A jv The novel features wh ch I believeto be characteristic of my invention are set-forth particularity in the appended. claims, the invention itself; however, asto :both its organization and method of operation will best be understood by reference to the, following description taken in connection withthe drawing in which I have indicated diagrammatically several circuit organizations. wherebjrhyinventibn may .be. carried into effe'ctu v Other objects and features of my. present invention will be apparent from the following description and discussion in connection withthe figuresof the accompanying drawing; in which like reference characters designate like elements soiarj as possible in the several figures."

'-'Fig's.-1,'2 and 3- diagrammatically illustrate the shielded grid type of tube andamplifier circuits in a variety of associations with asystem for energizing the electrodes from an unsteady source of current energy arranged'to employ the shield ing gridor fourth duction controll I Ineach of the figures the tube VT is shown with the conventional form of construction comprising an electron emissive cathode Kindirect- 1y heated by a heating wire'I-I energized by: alternating current from a transformer" Tngrid G,

plateP, and shielding: grid G. interposed between grid and plate. The plate electrodes are shown energized from a pulsating; sourceof potential S; an alternating current rectifier for example,

througlrthe conventional filter system shown as condensers C1 and C2 spanningone inductiveelement L. Grid bias potential is indicated asobtained in the conventionalmanner. of passing-the plate circuit current through a resistanceR shuntedby a signal current by-pass condenser C Each radio broadcast receivers element as an aid inhum pro-'- 7 of the systems are shown to have signal input and. output circuits conventionally including input transformers T and output transformers .T. I

In Fig. 1 the shielding grid G is shown connected to a point intermediate atresistancehRr s across the filter output selected to provide the usual degree ofzpositive potential for. this grid element for the desiredrsort ofoperationfland since usually very-little current flow is wantedin this auxiliarytgrid connection the resistance of R1 can ordinarily .be given 'a large value :to avoid undue current drain on the ,filter' system for developing the needed potential.

, While the development of grid bias potential across resistance R 'by flow therethrough of the pulsating plate circuit current introduces a pulsating potential component on the gridzacting to annul pulsations in theplate circuit current; yet these grid pulsations are not large enough I to obtain complete annulling, and are usually fur-- ther reduced by the general practice of employing asignal current by-pass condenser 03 to reduce signal derege'neration and distortion. -To makeup for this incomplete annulling of plate current pulsations, or no annulling if a separate source of steady grid biasing potential is used, I introduce into the shielding grid connection a pulsatinglcomponent of the same character as that applied to the plate electrodegas by coupling a winding S in this connection to the inductive element Lin the filter system, or any other equivalent way of extracting from the source adesired pulsating component. By choosing the polarityand magnitude of this extractedcomponent I can bring-to bear a desired annulling ef-. fect. on-the plate pulsations through controlled pulsations on the shielding grid, and thereby control hum to any desired degree, or avoid it, with? out interfering. in any derogatory way with signal current amplification or'other normal function of the tube and its circuits. 7

; 'In Fig. 2 I determine the positive bias of shielding grid G by a series drop of potential through resistance R'1 instead of the potentiometer arrangement Ri 0fFi-g.,1. The condenser G4 may supplement the coupling of coil Sto coil L to determineth degree of pulsations introduced on theshielding grid for hum control. I

In Fig. 3 I show one common practice of connecting a signal current by-pass condenser from the plate circuit direct to cathode to reduce signal currentdegeneration and distortion by lessening the amount of signal current common to the grid and plate circuitsyin grid bias producing resistance R.

Sucha connection increases the amount of fluctuating component of the plate circuit current that passes through resistance R, condenser C5 sufliciently grid will exceed that necessary for annulling the plate circuit pulsations. In this case there is no necessity for phase reversal of the pulsations R; is right to annul the over-annulling effect of the grid G. The degree of annulling pulsation on the shielding grid can be controlled by choice of condenser C'4.

Having fully described my invention I wish it understood that no limitations other than those imposed by the appended claims are intended by reason of the limited choice of adaptations thereof employed herein for descriptive and explanatory purposes, the invention being one of Wide application readily apparent to those acquainted with the art.

I claim:

1. An amplifier system including a vacuum tube having a cathode, control grid, anode and an anodeshield grid electrode, input and output signal' current circuits, connections for energizing resultant effect of said pulsating energizing of said control grid and anode electrodes.

2. An amplifier system including a vacuum tube having a cathode, control grid, anode and effect within said tube to the effect. of said pulsating energizing of said anode electrode.

3. An amplifier system including an electron path including a resistance connected across said source, and a connection between said screen grid electrode and said resistance.

4. An amplifier system including a thermionic tube having a cathode, control grid, anode and an anode screen grid electrode, input and output signal current circuits, connections for energizing said anode electrode and said control grid from a source of unidirectional pulsating energizing said screen grid electrode independentlyof said control grid tube to the effect of said pulsating energizing of said control grid and anode electrodes.

6. An amplifier system including a vacuum tube having a cathode, control grid, anode and tional pulsating current,

of said source and said screen electrode whereby the potential of to the eifect of said pulsating energizing of said control grid and anode electrodes.

said pulsating energizing of said control grid and anode electrodes.

8. An amplifier system including a vacuum tube screen electrode, said impressed pulsations be-:' ing opposed in efl'ect within said tube to the f unidirectional current,

which consists in heatingthe cathode to provide a strea'm or emetrens in t e tube, energiz ng Said anode and control electrode w'ith a pulsating A biasingfs'aidiscre'enf electrode positive with respect to said cathode, v and impressin upon said scren 'el'ectrode 'jsating potential component or such-polarityfand magnitude with respect-1 to the anode "energizing pulsations that the latterareefiectively ten:

trolled! l 'inethod of operating an'elfectro' I charge tube provided witljl**aj cathode; F control electrode,- anode, 1 and 7 an anode screen i electrode which consists in heating-the cathode to provide stream of electrons in the tube, energizing -s'aid anodeand control electrode witha-pulsating uni-- directional current; biasing "said-screen electrode positive with respect to sa d cathode; and im= pressing-upon said' screen electrode a pulsating potential component of such polarity and magnitude with respect to the anode energizing pulsations that the latter are effectivelycontrolled, and controlling the polarity and magnitude of said impressed component.

11. A method of operating an electron discharge tube provided with a cathode, control electrode, anode and an anode screen electrode, which consists in energizing thecathode to provide a stream of electrons in the tube, energizing said anode and control electrode with a pulsating uni-directional current, biasing said'screen electrode positive with respect to said cathode, and impressing upon said screen electrode a pulsating potential component of such polarity and magnitude with respect to undesired energizing pulsations of either the control electrode or anode that such undesired pulsations are effectively controlled.

. 12. A method of operating an electron discharge tube provided with a cathode, anode, and at least two cold electrodes disposed between the cathode and anode, which consists in heating the cathode to provide a stream of electrons in the tube, energizing the anode with a pulsating unidirectional current, biasing one of the cold electrodes negatively with respect to the cathode, biasing the remaining cold electrode positive with respect tothe cathode, and impressing upon one of said cold electrodes a pulsating potential com ponent of such polarity and magnitude as to eifectively control the occurrence of undesired energizing pulsations in the anode circuit of said tube.

13. A method of operating an electron discharge tube provided with a cathode, anode, and at least two cold electrodes disposed between the cathode and anode, which consists in heating the cathode to provide a stream of electrons in the tube, energizing the anode with a pulsating unidirectional current, biasing one of the cold electrodes negatively with respect to the cathode, with a pulsating uni-directional current, biasing the remaining cold electrode positive, with respect to the of said cold electrodes a pulsating potential component of such polarity and magnitude as to efiectively control the occurrence of undesired energizing pulsations in tube.

14. A method of operating an electron dissired energizing pulsations in the anode circuit of said charge tube provided with a cathode, anode, and at least two cold electrodes disposed between the cathode and anode, which consists in heating thecathode; to provide a stream of electrons in thetubeferiergizing the anode with a pulsating uni directional current,

H H biasing one of the cold electrodes negatively with respect to the cathode, biasing the remaining cold electrode positive with respect tothe cathode, but less positive than the anoda andirnpressingupon one of said cold electrodesa' pulsating p tential component of such pclarityfand"magnitude I as to effectively control thefoccurrenceof undesired energizing pulsations in the anode CilfqllitOf said tube. v l .A 'jmethod of operating an electron discharge tubeprovided with a cathode, anode, and at leasttwo cold electrodes disposedbetween the cathode and anodefwhich consists in heating the cathode :to provide a" stream of electrons in the tube, energizing the anode with a pulsating'unidirectional current, biasing one of the cold electrodes negatively with respect to the cathode, biasing the remaining cold electrodepositive with respect to the cathode, and impressing upon said remaining cold electrode apulsating potential component of such polarity and magnitude as to effectively control the occurrence of undethe anode circuit of said tube. g

16. A method of operating an electrondischarge tube provided with a cathode, anode, and at least two cold electrodes disposed between the cathode and anode, which consists in heating the cathode to provide a stream'of electrons in the tube, energizing the anode with a pulsating uni-directional current, biasing one of the cold electrodes negatively with respect to the cathode, with a uni-directional current including a pulsating component of such polarity and magnitude as to over-annul anode energizing pulsations, biasing the remaining cold electrode positive with respect to the cathode, and impressing upon the remaining cold electrode a pulsating potential component of such polarity and "magnitude as to effectively control the occurrence of undesired energizing pulsations in the anode circuit of said tube.

17. An amplifier system including an electron discharge tube having a cathode, control, grid, anode and screen grid, input and output signal current circuits, connections for energizing said.

anode-electrode from a source of uni-directional pulsating current, a resistance connection between the positive terminal of said source and said screen grid whereby the potential of said screen grid is controlled, a condenser series connected between said resistance and the negative terminal of said source, a grid bias resistor connected between the control grid and the cathode, an audio frequency by-pa'ss condenser connected between said anode and the positive terminal of said grid bias resistor, said screen grid being connected to said first mentioned resistance in such a manner that pulsations from said source are impressed upon said screen grid in such phase and magnitude as to oppose the effect within said tube of energizing pulsations on said control cathode, and impressing upon one g d 18. A method of operating an electron discharge tube provided with a cathode, anode, and at least two cold electrodes disposed between the cathode and anode, which consists in heating the cathode to provide a stream of electrons in the tube, energizing the anode with a pulsating un1- directional cturent, biasing one of the cold electrodes negatively with respect to the cathode,

effectively control the occurrence of undesired energizing pulsations in the anode circuit .of said tube.

19. In a power supply system for electron tubes, an electron tube having a cathode, anode, grid and shielding. grid, a source of pulsating direct current for energizingsaid anode, a source of pulsating direct current for energizing said shieldinggrid, and a current source for energizing said cathode, said source for energizing said shielding grid being connected to said shielding grid and to the circuit of said cathode, the pulsations being of magnitude and phase for neutralizing in the circuit of said anode the pulsations of the potential directly applied by said source for energizing said anode, whereby a smooth continuous anode current is produced.

20. Inga pomerisunply stem for electron tubes, an electron tube having a cathode, anode, grid and shielding grid, a source of pulsating direct current for energizing said anode, a current source for energizing said cathode, a source for energizing said shielding grid, an anode circuit connecting said anode to said source for energizanode, a shielding v rid circuit connect- .shieldinggrid to the circuit of .said cathode through said source for energizing said shielding :grid, .a coupling circuit coupled to said anode circuit and to'said shielding grid circuit for impressing pulsations in said anode circuit upon said shielding grid circuit, and phase adjusting means desired relation, whereby the :efiect upon the current in said anode circuit of the pulsations impressed upon said shielding grid neutralizes the pulsations in potential directly impressed upon said anode from said source for energizing said anode and a smooth continuous anode current is P oduced.

BENJAMIN F. MIESSNER. 

